Strongs Concordance:

Water, the river (Ezra 8:21) by the banks of which the Jewish exiles assembled under Ezra when about to return to Jerusalem from Babylon. In all probability this was one of the streams of Mesopotamia which flowed into the Euphrates somewhere in the north-west of Babylonia. It has, however, been supposed to be the name of a place (Ezra 8:15) now called Hit, on the Euphrates, east of Damascus.

(water), a place, (Ezra 8:15) or a river, Ezra 8:21 On the banks of which Ezra collected the second expedition which returned with him from Babylon to Jerusalem. Perhaps it is the modern Hit, on the Euphrates due east of Damascus.